Prior art subsea trees are installed on a wellhead with an annulus line and a production line. Prior art subsea trees provide a lateral connection which extends from the side of the subsea tree and provides a production flowline on the subsea tree prior to the subsea tree being lowered to the sea bed and installed. In many cases, the lateral connection also houses a choke. The rest of the production flowline typically runs along the sea bed where it may eventually be connected to a distribution manifold, a tanker or a surface facility.
The lateral connection between the production line and the production flowline, with all the accessory items, is secured to the subsea tree. If it is desirable to change the configuration or to replace or maintain certain of the accessory items such as the choke or other accessories, the entire subsea tree will need to be retrieved. Thus, changes to a subsea configuration will generally involve substantial and rather costly operations due to the cost of removing the subsea tree. To the extent high wear items are provided, such as chokes and/or other high wear items, it is expensive to remove the entire tree to replace a wear item. In some cases, removable chokes and choke inserts may be utilized to avoid the costs of removing the entire tree but removable chokes and/or other removable accessories each then require special mounting equipment and connections, such as retrievable Subsea Control Modules and retrievable choke inserts.
Referring to FIG. 1, there is shown a schematic configuration of a typical prior art subsea well 10 comprising subsea tree 40 mounted on wellhead 12. Subsea tree 40 comprises an annulus line 14 and a production line 16. At the side of subsea tree 40, a fixed lateral connection 18 goes through valve 20, which may be a production wing valve. Fixed lateral connection 18 then leads to production flowline 22. Production line 16 may comprise production service valve and production master valve 24. The production of the well flows from production line 16 into production flowline 22. The fixed lateral connection 18 may also comprise a choke, which creates back pressure and provides a desired flow rate. Access to the well bore from a surface rig may be provided through production line 16. Annulus line 14 may comprise annulus service valve 26, annulus master valve 28, and other annulus access valves, as indicated at 30, which are utilized to access the annulus of the well. Additional barriers from downhole valves 32 or plugs may be utilized in wellhead 12 to shut in the well for replacement of tree 40, and the like. Connection 34 schematically represents the physical connection of subsea tree 40 to wellhead 12, and may take the form of various types of connectors, which may be operated hydraulically or mechanically and/or fitted using remotely operated vehicles.
The following patents disclose prior art attempts to solve the above discussed problems.
U.S. Patent Publication No. 2005/0109514, published May 26, 2005, to White et al, discloses a subsea production tree that has an external annular profile formed on an upper portion of the tree. A vertical passage extending from a lower end of the tree to an upper end of the tree for communicating with a string of tubing extending into the well. A lateral passage in the tree extending from the vertical passage. A flow path in fluid communication with the lateral passage extends laterally from the tree, the flow path having an upward facing receptacle. An adapter lands on the upper portion of the tree and connects to the profile, the adapter having a passage that registers with the vertical passage of the tree while the adapter lands on the tree. A flow interface device mounts to and lands with the adapter, the flow interface device having an inlet conduit and an outlet conduit, one of the conduits being connected to the passage in the adapter, the other of the conduits stabbing into sealing engagement with the receptacle as the adapter lands on the tree.
U.S. Patent Publication No. 2009/0025936, published Jan. 29, 2009, to Donald et al, discloses a connection system for connecting flow interface equipment to a subsea manifold. The connection system relates particularly to a connection apparatus adapted to land a conduit means on a subsea manifold in a first stage of the connection and to connect a conduit means of the connection apparatus to a choke body of the manifold in a second stage of the connection.
U.S. Patent Publication No. 2008/0302535, published Dec. 11, 2008, to Barnes, discloses a multi-component system for subsea intervention. The system comprises a lower riser component which is held vertical by a buoyancy element and an upper riser system. The upper riser system is a continuous, enjoined conduit with sufficient flexibility to absorb the motion of the deployment vessel without adversely affecting the function of the intervention system.
U.S. Patent Publication No. 2008/0277122, published Nov. 13, 2008, to Tinnen, discloses an apparatus and a method for subsea deployment and/or intervention through a wellhead of a petroleum well. The apparatus comprises a first module integrated in a portion of a subsea well intervention system assembly and/or a subsea production system assembly, the first module comprising an intervention tool bore; a second module comprising a tubular element initially housing an intervention tool, wherein the second module being arranged for sliding into releasable engagement with the intervention tool bore of the first module, whereupon the intervention tool is arranged for disengagement from the tubular element for deployment of the intervention tool into the wellbore.
U.S. Pat. No. 6,655,455, issued Dec. 2, 2003, to Bartlett et al, discloses a flow completion system for controlling the flow of fluid from a well bore, the flow completion system comprising a tubing spool, a tubing hanger supporting a tubing string which extends into the well bore and defines a tubing annulus surrounding the tubing string; a first closure member which is positioned in the production bore above the production passageway; a first annular seal wherein the first closure member and the first seal comprise a first pressure-containing barrier between the well bore and a surrounding environment; a second closure member which is positioned in the production bore above the first closure member; and a second annular seal wherein the second closure member and the second seal comprise a second pressure-containing barrier between the well bore and the environment; and wherein both the first and the second barriers are associated with the tubing hanger.
U.S. Pat. No. 7,032,673, issued Apr. 25, 2006, to Dezen et al, discloses an outer wellhead housing has an external locator member initially oriented in a desired direction. An inner wellhead housing lands in the outer wellhead housing. A BOP orientation spool with an external orientation member and an internal orientation member lands on the inner wellhead housing and orients via the external locator member. A tubing hanger with an orientation member and associated tubing hanger running tool with another orientation member lower through the BOP orientation spool and orient as they land in the inner wellhead housing. A production tree with an orientation member on a lower end lands on the inner wellhead housing. The orientation member of the production tree engages the orientation member of the tubing hanger to rotate the tree to a desired orientation.
U.S. Patent Publication No. 2010/0018693, published Jan. 28, 2010, to Duncan et al, discloses an apparatus for inserting coiled tubing into a sub-sea pipeline comprising an adaptor which is releasably coupled to an anchor to hold the adaptor in position against lateral and/or vertical forces, the adaptor having: i) a first end comprising first coupling means for releasably coupling the adaptor to a riser and an opening through which coiled tubing can extend, ii) a second end comprising second coupling means for releasably coupling the adaptor to the anchor, and iii) a curved guide comprising an entrance end facing the opening and an exit end, the curved guide being in communication with the opening such that coiled tubing from the riser can extend through the opening and along the curved guide, the curved guide, in use, guiding the coiled tubing from a substantially vertical orientation at the entrance end to a substantially horizontal or near-horizontal orientation at the exit end.
U.S. Pat. No. 4,161,367, issued Jul. 17, 1979, to Cuiper et al, discloses a diverless subsea flowline connection system that includes connectors for remotely connecting the ends of a first bundle of flowlines to the ends of a second bundle of flowlines and guidance components which direct the end portions of the first bundle of flowlines into precise connecting alignment with the end portions of the second bundle of flowlines without damage to the connecting seals. The ends of the first bundle are covered and sealed so that the flowlines can be pulled across the seafloor without damage to the ends of the flowlines. Means are provided for pulling the first bundle toward an alignment structure so that the lines can approach the structure from a wide variety of angles and the structure will guide the first bundle into exact alignment with the second bundle. This pulling means includes means for connecting a pulling cable to the radial center of a pulling head attached to the ends of the first bundle of flowlines. The ends of the flowlines are connected together and aligned before the fluid-tight seals are set to prevent possible damage to the seals. After the flowline ends are precisely aligned the seals are set. If desired, the connecting seals can be replaced by remote control. The pulling, aligning, replacement of seals and fluid-tight connecting of the flowlines is all done by remote control from the surface of the sea.
The above listed prior art efforts do not solve the above discussed problems. Consequently, those of skill in the art will appreciate the present invention which is directed to reduce the significant cost created by the above prior art limitations.